Electrical problems. PLEASE HELP

So I just got a 82' sx400S that the PO said had some issues. He said the bike had a power drain somewhere and that the bike would stop running once the battery went dead. then he messed up the timing tinkering with the points so now it won't start.

My initial plan is to get this thing started then check the charging system. The timing cover is off and the PO apparently undid the two bolts and rotated the plate that has 3 nuts on the backside. He said that he wasn't sure how to put it back on. Does the rotation matter? If so, how do I get it back? Picture is attached.

As for the discharge:
All the wiring looks legit so I wonder if it could be either the regulator or something in the charging system.

Also there is a random tube sticking out. Should that go somewhere?

Lastly, he had the idle adjustment backed out all the way. Is there a good default position to start it at to get the bike started easier.

Rubgy - here are my first thoughts. Others will get you better specifics.

The power drain sounds to me like your charging circuit is not working. Get a manual and perform the checks listed there. I'm guessing your stator has a short (but that's just a guess).

Those aren't points in the first pic. Those are the electronics that replace your points (TCI???). Anyway, you'll have to remove the timing cover from the left side of the engine and use the marks you find there to properly set the timing. The timing is adjusted by loosening the two screws on the timing plate (TCI???) so you can adjust when the spark plugs fire.

That random tube used to connect to the stock airbox that housed the stock airfilters. I think most folks put some sort of PCV valve on there when they remove the stock airbox.

Sorry I don't have better specifics with me. These bikes really are easy to work on, so just stay persistent. Others here will follow with better directions.

Good Luck!

Disaster!! I think I got ripped off by the PO. Either he never had the bike running or he tried to fix it and he REALLY didn't know anything about bikes. So I read the forums and looked around and figured out how to get it timed. Good but the bike still wouldn't start. I then took off the air filters and sprayed in some ether (I know it's not good but I was desperate) and voila it fired but still not started. I figured it must be the carbs. Lo and behold the right side float was upside down so the cylinder wasn't getting gas. Put it back together and it started... but only with the choke on. This is where it went downhill fast. I put my hand at the exhaust pipes and only the right side was firing. Furthermore, the compression from the left side was coming back out of the carb. So I get to looking and I had noticed the plug just up and to the left of my TCI was missing earlier and didn't think anything of it but I pulled the one on the other side just to compare. That is when I found it. There is some sort of sleeve that holds what appears to push the valves open that is completely missing on the left side cylinder. My guess is that is the valve where the exhaust goes to the pipe is not opening to let the exhaust out. That would explain why I couldn't feel it. Obviously that cylinder isn't firing either so that explains why I had to have the choke on.

The metal piece that sits on the spring is still there, It looks like just the piece that it hinges to is missing (what you would see looking behind the plug). Can anyone tell me what that is and if I can get one without having to buy a engine rebuild kit? I won't get it started until then. Thanks

the manual says its a rocker arm spindle. All the sites I have found say they are not available. What do I do now? Can I just get one made or something? Thanks.

I have one. It's in good shape $12.50 shipped paypal only.

Thats great!! I'll Take it. How do I proceed to buy? Do you happen to have a plug to go in the tci box as well?

Also, will I be able to just shove it in there or will I have to take the entire top of the engine off to get it in?

Yes I have the plug that goes behind the pickup cover. You can have it for $2 more You might be able to get it in without removing the rocker box. Thread a 10mm bolt in the end of the shaft and grab the rocker through the adjustment hole and slide it in. You can rotate the engine so the cam is in that valves closed postion. Make sure the pin is oiled well before sliding it in.

P.M. sent on paypal info

Lastly, he had the idle adjustment backed out all the way. Is there a good default position to start it at to get the bike started easier.

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Nope, If you still have a working Tachometer, then set it to about 900 to 1200 RPM's. (warmed-up) Closer to 1200 so that when its cold it won't be inclined to stop out on you. Since someone upgraded to POD's so that puts a spin onto things, that requires adjustment to jets, and other items. So there is no standard turn this knob to this point. Hope that helps, I am sure someone will answer that last question, its a little more than I have done yet! so good luck!

xschris said:

P.M. sent on paypal info

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Done. Thanks

I have a cover also. I see you need one of them. That guy you asked is selling dohc parts not sohc like you have. $15 for the cover if you want it.

xschris said:

I have a cover also. I see you need one of them. That guy you asked is selling dohc parts not sohc like you have. $15 for the cover if you want it.

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Let me get this bike started and I'll let you know. I don't want to go buying a bunch of parts to find out the bikes junk or something, but I will definitely keep that in mind. Thanks

After reading here about chris magically supplying the most random bits and pieces of xs that I've never even heard of for the 100th time, I can only imagine him living in an abandoned yamaha factory from the 70's, surrounded by piles of dismantled xs400s...

percisely what I envision. lol!

Not quite but close. After 15 years of owning these bikes you collect a lot of stuff. Also 2 years ago I bought all the used xs400 parts my local yamaha dealer had

So i got the part today and the started right up. Thats GREAT!! Its backfiring a bit and sometimes when I rev it up it doesn't come back down to idle all the way. I will need to take a look at the cable and I noticed the carb holders are dry rotted and cracked so I will see if that fixes the problems. This bike has a of "potential". Just needs some TLC. Thanks for all the help.

intake boots weathered and cracked? you'll be sucking air through those, causing it to run lean, which causes the backfires and the high rise idle. Yes replacing them will definitely help!

A good carb cleaning cleaning and adjustment will also help. Make sure you have air filters on the bike also. Did you adjust the valves yet?

xschris said:

A good carb cleaning cleaning and adjustment will also help. Make sure you have air filters on the bike also. Did you adjust the valves yet?

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I figured if I can get it to run pretty well, I'll save the carb cleaning until it gets a little colder outside as one of the winter projects.

I did have it running with and w/o filters. That def helped but not completely

Not yet, the valves are on my fairly extensive list of stuff I need to do/check. Along with changing the oil, getting the headlight working, adjusting the clutch and cables...etc.

I'm actually kind of excited. This being my first bike, I feel like I'm going to know it pretty intimately before I even hit the road.